The present invention relates to hydraulic gear machines in general, that is, to machines utilizing meshing gears for effecting conversion between the potential energy of a pressurized hydraulic medium and the kinetic energy of a rotating shaft, and more particularly to a hydraulic gear machine which is especially suited for use as a hydraulic gear motor.
There are already known various constructions of hydraulic gear machines of the type here under consideration, in which two gear elements are in external meshing engagement with one another and have respective stub shafts which are supported in the housing of the machine on respective bearings which are mounted in the housing for limited axial displacement relative thereto. It is also known to provide axially effective pressure zones acted upon by the pressurized hydraulic medium from the high pressure side of the machine for pressing the bearings against the gear elements at the end surfaces of the bearings which face away from the gear elements, these pressure zones being delimited by respective seals and extending only over a portion of the total available area of the respective bearings.
In one conventional construction of the gear machine of this type, there is provided in the housing, in addition to the bearing elements, a pressure plate on which pressure zones are delimited by a seal arranged in an associated end wall or lid portion of the housing of the machine. The pressure of the pressurized hydraulic medium which acts on the respective pressure zone of the pressure plate is transmitted by the latter to the bearings to press the same into a sealing contact with the axial end faces of the gear elements. An arrangement of this particular type is particularly suited for use as a reversible gear motor, since the pressure of the hydraulic medium is always applied to the pressure zone situated at the proper side. However, this arrangement is rather expensive, since it requires the provision of components which are especially designed and manufactured for use in a gear motor.